Dispensing a precise and accurate amount of material has many uses. Currently, there are at least two common ways that units of material(s) are dispensed. AS used herein, the terms “unit” and “item” are used to indicate a discrete quantity of a solid or semi-solid material, e.g. one pill or one box. In one method, a human or robotic arm may select units. In a second common method, items may be dispensed at a fixed volume or mass. Some volumetric dispensers do not permit the adjustment of the mass or volume to be dispensed as dispensing needs change. Additionally, many methods may require human input to verify accuracy and precision of the dispense. Human input can result in errors, inaccuracies, and time inefficiency.
Dispensing a precise and accurate number of units has many uses. Examples of units for which automated dispensing is useful include, but are not limited to: pills, capsules, surgical supplies, medical supplies, food stuffs, shipping materials, and manufactured parts. Currently, there are known mechanisms for the automated or partially-automated dispensing of units. These mechanisms are based on, but are not limited to, selection by: mass, volume, density, imaging, and unique item selection.
For certain material(s), uses, and limitations, volumetric selection is appropriate. Volumetric dispensing devices have been proposed before. Some known devices have several disadvantages, such as: inability or difficulty with modifying the desired volumes for dispensing, inaccurate dispenses, and jamming.
Some previous volumetric dispensing devices have made it difficult or impossible to adjust the dimensions of the device to accommodate units of different size. Since materials to be dispensed may have different physical dimensions or shapes, such devices may be unsatisfactory for one's dispensing needs. Furthermore, non-automated adjustments of the dimensions of the device can make it difficult and/or time consuming for individuals to properly adjust controlling the dimensions of the dispensing device and, thus, to properly dispense the desired materials.
Some known adjustable volumetric dispensing devices have also made it difficult or impossible to dispense a wide range of shapes and dimensions of material(s) due to the eccentricity of the dispensing mechanism. At least one known volumetric dispensing device has two, stacked movable dispensing rings comprising circular openings. Relative rotation of the rings allows for a changeable dispensing opening, which can only form a circular dispensing opening when the two circular openings are perfectly aligned. For all other alignments, a range of elliptical dispensing openings are formed when the circular openings are not aligned. Since the dispensing rings are stacked, the circular openings are offset somewhat in the vertical direction. Mechanisms which rely on this type of elliptically shaped dispensing openings for dispensing materials of different sizes and shapes can result in inaccurate dispensing. As the eccentricity of the dispensing plane increases, the dispensing opening becomes less accurate in its dispensing of less eccentric units. Such mechanisms are also prone to jamming and risk damaging the units being dispensed. This is illustrated below with reference to FIGS. 1-4.
As one example of units to be dispensed which have known dimensions, pharmaceutical pills come in a wide variety of shapes and sizes. For example, one known pill is shaped like a right circular cylinder and has a radius of 2 mm. Another pill is in the shape of a capsule and has a major axis length of 19 mm. Another pill is shaped like a right circular cylinder and has a radius of 20 mm. A still further pill is shaped like a three-pointed star.
FIGS. 1A-4A illustrate three different shaped pills positioned in elliptical openings. For simplification, the elliptical openings are shown as being formed of two gates which are in the same plane, but the prior art known to the present inventors forms these opening with gates which are vertically offset, i.e. not in the same plane, of the type described in the prior art with each Fig. A showing the shape of the pill, each Fig. B showing a top view, each Fig. C showing a perspective view and each Fig. D showing a side view.
FIGS. 1 and 2 illustrate the same pill having the indicated dimensions shown in FIG. 1A. The drug Bayer® Asprin is an example of a pill having these dimensions. It is assumed that gravity will make it more likely that a pill or other unit will be in its position of lowest potential energy, i.e., “lying down”, in a dispenser reservoir, therefore it is most desirable to provide dispensing openings which are sized to receive the pill when it is in this orientation. FIGS. 1B-1D illustrate that when an elliptical opening is opened sufficiently to receive the pill shown in FIG. 1A, the elliptical opening will also have room to receive two additional pills in a vertical orientation. The extra space or gaps left in the elliptical opening by a single pill in the “lying down” orientation shown in FIGS. 1B-1D is problematic in that it creates a greater likelihood that more than the desired single pill will be dispensed, as well as a greater risk of jamming or pill breakage if another gate tried to move above the illustrated gates. Pill breakage will also increase the likelihood of inaccurate dispensing since a piece of a pill may slip into a gap of a dispensing opening.
FIGS. 2A-2D illustrate the same pill shown in FIG. 1 and show that it is possible to configure an elliptical opening to receive a vertically oriented pill and thereby leave less of a gap. As noted above, it is believed that it is more difficult to get a pill to enter a dispensing gate in this vertical orientation.
FIGS. 3A-3D show a pill having dimensions x2, y2, z2, where 2y2 is less than x2. As shown in FIGS. 3B-3D, an opening which can receive this pill in the “lying down” position will accept two of these same pills in a vertical orientation, thus posing a risk of inaccurately dispensing two pills when it is desired to dispense a single pill.
FIG. 4A shows a pill in the shape of a three-pointed star where x2 equals y2. The drug Xarelto is an example of a pill having these dimensions. FIGS. 4B-4D show that an elliptical opening sized to receive one of these pills in the horizontal or “lying down” orientation will necessarily be dimensioned to receive two of these pills in the same orientation.